CN114635123A - Film-forming device and film-forming method for metal coating - Google Patents

Abstract

The present invention relates to a film forming apparatus and a film forming method for a metal plating film. An apparatus and method for forming a metal plating film having a thick film thickness using a solid phase displacement type electroless plating method are provided. A film forming apparatus for forming a first metal on a plating film of a second metal by a solid-phase displacement electroless plating method, comprising: the plating bath is provided with a first metal plating film, a second metal plating film, a third metal plating film, an insulating material, a microporous film, a plating bath chamber, and a pressing means.

Description

Film-forming device and film-forming method for metal coating

technical field

The present invention relates to a film-forming apparatus and a film-forming method of a metal plating film (also simply referred to as a "film" in this specification and the like).

Background technique

Generally, methods for performing plating by reducing metal ions in a plating bath (here, "plating bath" is also referred to as "plating solution") are roughly classified into electroplating methods that use an electric current from the outside and electroplating methods that do not use an electric current from the outside. electroless plating method. The latter electroless plating method is further roughly classified into (1) a substitutional electroless plating method in which metal ions in a solution are reduced to precipitate on a to-be-plated object by utilizing electrons released accompanying the dissolution of the to-be-plated object, and (2) An autocatalytic reduction-type electroless plating method in which metal ions in a solution are deposited as a metal film by utilizing electrons released when a reducing agent contained in a solution is oxidized. The electroless plating method enables uniform precipitation even on surfaces of complex shapes, and is widely used in many fields.

The displacement type electroless plating utilizes the difference in ionization tendency of the metal in the plating bath and the base metal to form a metal plating film. For example, in the gold plating method, when the substrate on which the base metal is formed is immersed in the plating bath, the base metal with a high ionization tendency becomes ions, which dissolve in the plating bath, and the gold ions in the plating bath act as metals on the base metal. precipitation to form a gold plated film. Substitution type electroless plating is widely used mainly as a base for preventing oxidation of base metal and for autocatalytic plating.

For example, Patent Document 1 discloses a displacement-type electroless plating bath using a displacement-type electroless plating method. Patent Document 1 discloses an electroless gold plating bath, which is an electroless gold plating bath for forming a gold plating film on an electroless nickel plating film, characterized by containing (a) a water-soluble gold compound, (b) an acid dissociation constant (pKa) a conductive salt composed of an acidic substance having a pKa of 2.2 or less, and (c) an oxidation inhibitor composed of a heterocyclic aromatic compound having two or more nitrogen atoms in the molecule are essential components.

Patent Document 2 discloses a method of manufacturing a semiconductor device using an electroless plating method. Patent Document 2 discloses a method of manufacturing a semiconductor device, characterized in that, when manufacturing a semiconductor device having a surface electrode on a semiconductor substrate, it includes a step of forming a metal electrode film on the surface of the semiconductor substrate, and a step of forming a metal electrode film on the surface of the metal electrode film. In the plating layer forming step of forming a nickel plating layer by electroless nickel plating, the total element concentration of sodium and potassium remaining on the surface of the metal electrode film before the plating layer forming step is 9.20×10 ¹⁴ atoms/cm ² or less, and the above-mentioned no The total element concentration of sodium and potassium contained in the electroless nickel plating bath used for the nickel electroplating treatment is 3400 wtppm or less.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2005-307309

Patent Document 2: Japanese Patent Laid-Open No. 2011-42831

SUMMARY OF THE INVENTION

The problem to be solved by the invention

The formation of a metal plating film by electroplating has the advantage of a high film-forming speed. On the other hand, it has the disadvantage that it is difficult to form a metal film uniformly. Local corrosion occurs, it becomes difficult to form a uniform gold film, and the solder wettability decreases.

Formation of a metal plating film by electroless plating has the advantage of being able to form a metal film uniformly. On the other hand, it has the following disadvantages: the film formation speed is slow, it is difficult to obtain a thick film thickness, and the cost is high. This is because when the base is covered with metal by electroless plating, the precipitation reaction of the metal is stopped, and the film thickness is only about 0.2 μm at the maximum.

Therefore, in recent years, among the electroless plating methods, attention has been focused on a solid phase method capable of forming a metal plating film at high speed.

The solid phase electroless plating method (Solid Electroless Deposition: SELD) includes a solid phase replacement type electroless plating method and a solid phase reduction type electroless plating method. The solid-phase replacement type electroless plating method is performed by using a replacement type electroless plating bath containing ions of the first metal and a second metal having a greater ionization tendency than the first metal (or a second metal plated on a metal substrate). A microporous membrane such as a solid electrolyte membrane is provided between the two, and a redox reaction caused by the difference in the ionization tendency of the metal between the ions of the first metal in the microporous membrane and the second metal as the base metal occurs, so that the first metal is A method of forming a metal plating film made of the first metal on the surface of the second metal by precipitation on the surface of the second metal. The solid-phase reduction type electroless plating method is a method of disposing a microporous film between a reduction type electroless plating bath containing ions of a second metal and a metal substrate, and the ions of the second metal passing through the microporous film and the reduction type electroless plating bath. A method of forming a plating film of the second metal on the surface of the metal substrate by causing a redox reaction of the contained reducing agent to precipitate the second metal on the surface of the metal substrate.

An object of the present invention is to provide an apparatus and method for forming a metal plating film having a thick film thickness by a solid-phase method, particularly a solid-phase displacement electroless plating method.

means of solving problems

The inventors of the present invention have conducted various studies on means for solving the above-mentioned problems, and as a result, have found that when the first metal is formed by the solid phase displacement electroless plating method on the plated film of the second metal, the following film forming apparatus is used. A film device comprising: a conductive loading stage for placing a substrate having a coating film of a second metal; The third metal; provided on the conductive stage, between the base material and the third metal when the base material with the coating of the second metal is set to be connected with each material [ie, the base material (the Insulating material provided so as to be in contact with the third metal plated film) and the third metal; displacement type electroless plating for dipping the ions of the first metal to be delivered to the second metal plated film on the substrate The microporous membrane of the bath; the plating bath for accommodating a displacement type electroless plating bath containing ions of the first metal with the openings provided with the microporous membrane; after the microporous membrane is brought into contact with the plating film of the second metal on the substrate, it is used As a result of the extrusion means for extruding the plating bath and the base material, the local cathodic reaction of the first metal caused by the local anodic reaction of the third metal occurs, which promotes the replacement reaction of the first metal and the second metal, and can form a The coating of the first metal with a thick film thickness completes the present invention.

That is, the gist of the present invention is as follows.

(1) A film forming apparatus, which is a film forming apparatus for forming a first metal on a plated film of a second metal by a solid-phase displacement type electroless plating method, and includes a conductive film for forming a base material having a plated film of the second metal. a conductive loading stage, a third metal provided on the conductive loading stage, an insulating material provided on the conductive loading stage, a first metal containing first metal for dipping delivery to the coating of the second metal on the substrate A microporous membrane of an ion-substitution type electroless plating bath, a plating bath for accommodating a substitution type electroless plating bath containing ions of a first metal, and a microporous membrane provided with a microporous membrane in the opening, and the microporous membrane and the first metal on the substrate The extrusion means for extruding the coating bath and the base material after the contact of the two metal coatings, the third metal has a larger ionization tendency than the first metal and the second metal, and the coating with the second metal is provided when the coating has a second metal. The insulating material is provided between the substrate and the third metal so as to be in contact with the respective materials.

(2) The film forming apparatus according to (1), wherein when the base material having the plated film of the second metal is provided, the base material having the plated film of the second metal and the third metal and the insulating material have the same height, on the same level.

(3) The film forming apparatus according to (1) or (2), wherein the conductive stage has a convex portion having the same width as that of the third metal at a portion where the third metal is provided, wherein the width is The length in the direction in which the base material, the insulating material, and the third metal are arranged, and the third metal is provided on the convex portion of the conductive mount.

(4) The film forming apparatus according to any one of (1) to (3), wherein the third metal is aluminum or iron.

(5) The film forming apparatus according to any one of (1) to (4), wherein the insulating material contains an insulating polymer.

(6) The film forming apparatus according to any one of (1) to (5), wherein the base material is a copper base material, the first metal is gold, and the second metal is nickel.

(7) A method of forming a first metal on a plated film of a second metal using a solid phase displacement electroless plating method, comprising: (i) disposing a plated film having the second metal on a conductive stage The process of forming a base material, wherein the base material is arranged so that the surface opposite to the side where the plating film of the second metal is formed of the base material is in contact with the conductive stage; (ii) the third metal is set on the conductive stage the process of which the third metal has a larger ionization tendency than the first metal and the second metal; (iii) the process of disposing the insulating material on the conductive stage, wherein the insulating material is disposed on the base material and the third metal so as to be in contact with the respective materials; (iv) the process of disposing the microporous film, wherein the microporous film is disposed so as to be in contact with the coating film of the second metal on the substrate; (v) disposing the first A process of a substitutional electroless plating bath for metal ions, wherein a substitutional electroless plating bath containing ions of a first metal is provided so as to be in contact with a microporous membrane; and (vi) a substitutional electroless plating bath containing ions of the first metal is to be accommodated The process in which the plating bath of the electroless plating bath and the substrate are pressed against each other.

(8) The method according to (7), wherein the third metal is aluminum or iron.

(9) The method according to (7) or (8), wherein the base material is a copper base material, the first metal is gold, and the second metal is nickel.

Invention effect

According to the present invention, there is provided an apparatus and method for forming a metal plating film having a thick film thickness using a solid phase displacement type electroless plating method.

Description of drawings

FIG. 1 is a cross-sectional view schematically showing a state in which a solid-phase displacement electroless plating method is carried out using an example of the film forming apparatus of the present invention.

FIG. 2 is an enlarged view of a portion indicated by a dotted line in FIG. 1 .

FIG. 3 is a diagram illustrating the movement of electrons in the solid-phase displacement type electroless plating method of the present invention using a further enlarged view of the portion indicated by the dotted line in FIG. 2 .

FIG. 4 is a photograph of a gold plated film formed according to Example 1. FIG.

Description of reference numerals

1: Substrate with plated film of second metal, 1': Copper substrate with plated film of nickel, 2: Substitution type electroless plating bath containing ions of first metal, 2': Substitution type electroless gold plating bath, 3: Conductive mount, 3': Titanium mount, 4: Insulating material, 4': PEEK, 5: Protruding portion of the conductive mount, 5': Protruding portion of the titanium mount, 6: No. Three metals, 6': aluminum plate, 7: another insulating material, 8: microporous membrane, 9: fixture, 10: plating bath, 11: pressure, 12: nickel coating, 13: gold coating

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail.

In this specification, the features of the present invention will be described with reference to the accompanying drawings as appropriate. In the drawings, the size and shape of each part are exaggerated for clarity, and the actual size and shape are not drawn accurately. Therefore, the technical scope of the present invention is not limited to the size and shape of each part shown in these drawings. In addition, the film forming apparatus and film forming method of the metal plating film of the present invention are not limited to the following embodiments, and changes and improvements that can be made by those skilled in the art can be implemented within the scope of not departing from the gist of the present invention. implemented in various ways.

The present invention relates to a film forming apparatus for forming a first metal on a plated film of a second metal by a solid-phase displacement electroless plating method, comprising: an electrical conductor for providing a base material having a plated film of the second metal. a conductive loading stage, a third metal provided on the conductive loading stage, an insulating material provided on the conductive loading stage, a first metal containing first metal for dipping delivery to the coating of the second metal on the substrate A microporous membrane of an ion-substitution type electroless plating bath, a plating bath for accommodating a substitution type electroless plating bath containing ions of a first metal, and a microporous membrane provided with a microporous membrane in the opening, and the microporous membrane and the first metal on the substrate The extrusion means for extruding the coating bath and the base material after the contact of the two metal coatings, the third metal has a larger ionization tendency than the first metal and the second metal, and the coating with the second metal is provided when the coating has a second metal. The insulating material is provided between the substrate and the third metal so as to be in contact with the respective materials.

Hereinafter, the constituent materials of the film forming apparatus of the present invention will be described in detail.

(loading table)

The loading stage is a stage on which a base material having a coating film of the second metal is placed, and has conductivity. The loading table is not limited as long as it is made of a conductive material, and for example, a loading table made of titanium or stainless steel can be mentioned.

Since the stage has conductivity, electrons released from the third metal move through the stage to the substrate and the plated film of the second metal formed on the substrate, and the film formation of the first metal on the second metal plated film can be promoted. .

The mounting table preferably has a convex portion having the same width as the width of the third metal (wherein the width is the length in the arrangement direction of the base material, the insulating material and the third metal) at the portion where the third metal is provided, for example, although not limited, it has a convex portion. Usually 0.1 mm - 10 mm, Preferably the convex part of the height of 1 mm - 2 mm.

By having the above-mentioned convex portion on the mounting table, the sealing performance between the mounting table and the insulating material and the third metal is improved, and the penetration of the displacement electroless plating bath into the film forming apparatus can be prevented. Furthermore, the amount of the third metal to be used can be reduced by having the above-described convex portion on the mounting table.

(third metal)

The third metal is a metal for forming a local battery between the plating film of the second metal and the second metal on the substrate via the conductive mounting table, and is provided on the conductive mounting table, compared with the first metal and the second metal. , has a large ionization tendency. In addition, an alloy containing two or more metals is included in the third metal.

The standard electrode potential (Z) [V with respect to NHE] of the third metal is usually -3.045V≦Z<-0.277V, preferably -2.714V≦Z≦-0.338V.

Examples of the third metal include magnesium, beryllium, aluminum, titanium, zirconium, manganese, zinc, iron, and the like. As the third metal, aluminum or iron is preferable from the viewpoint of supply and ease of processing. As the third metal, aluminum is more preferable.

The third metal is preferably provided in a detachable form on the conductive stage. Since the third metal is detachable, even if the third metal is consumed by implementing the solid-phase replacement type electroless plating method, the consumed third metal can be easily replaced with a new third metal.

The third metal is placed in contact with at least one, for example, two, insulating materials in contact with the base material on the conductive stage. The third metal is preferably provided in close contact with the insulating material.

The shape of the third metal can have any shape depending on the shape of the conductive stage and the insulating material. The shape of the third metal is, for example, a flat or curved plate.

When the third metal is a plate-like object, the average thickness (height) of the third metal is not limited, but is usually 0.1 mm to 10 mm, preferably 1 mm to 5 mm. The length in the direction in which the material and the third metal are arranged) is not limited, but is usually 2 mm to 10 mm, and the depth (wherein, the depth is the length in the direction perpendicular to the width) is not limited, and is usually shorter than the depth of the base material. 0mm～5mm. The third metal preferably has the same height as that of the insulating material and the substrate having the plated film of the second metal when the substrate having the plated film of the second metal is installed in the film forming apparatus of the present invention. Furthermore, the conductive mounting table has a convex portion having the same width as the width of the third metal (where the width is the length in the arrangement direction of the base material, the insulating material and the third metal) at the portion where the third metal is provided. In this case, when the base material having the plated film of the second metal is set in the film forming apparatus of the present invention, the third metal preferably has a connection between the insulating material and the plated film having the second metal together with the height of the convex portion. The height of the substrate is the same height. Since the third metal has such a height, the microporous membrane is not only the plated film of the second metal on the substrate, but also the insulating material provided in contact with the substrate and the third metal provided in contact with the insulating material. When the metal is also in contact, the microporous membrane is in contact with the plated film of the second metal, the insulating material, and the third metal on the substrate, which are arranged at the same height so as to be on the same level. The contact surface between the microporous membrane and these materials no longer has irregularities. If the contact surface of the microporous membrane and these materials has no irregularities, breakage of the microporous membrane can be suppressed. Furthermore, by carrying out the method of the present invention, the site that can be contaminated becomes only the contact surface between the microporous membrane and these materials, so cleaning becomes easy.

(insulating material)

The insulating material is a material provided to prevent corrosion of the contact portion that can occur by direct contact between the base material and the third metal, and especially corrosion that can occur significantly when a liquid component such as a plating bath penetrates the contact portion. On the conductive stage, it is placed in contact with the third metal, preferably in close contact with the third metal. When a base material having a plated film of the second metal is installed, the base material (the part of the base material where the plated film of the second metal has not yet been formed) is installed. surface) and the third metal, so as to be in contact with each material [that is, the substrate (the surface of the substrate on which the plating film of the second metal has not been formed) and the third metal], that is, in a conductive loading On the stage, phase in the order of base material-insulating material-third metal, or third metal-insulating material-base material, or third metal-insulating material-base material-insulating material-third metal, respectively. It is grounded, preferably installed so as to be closely arranged.

The insulating material is not particularly limited as long as it has insulating properties, but for example, insulating polymers are preferable. The insulating polymer is a polymer that does not flow electricity. The insulating polymer is not particularly limited, and examples thereof include polyolefins such as polypropylene (PP) and polytetrafluoroethylene (PTFE), polyamide (PA), polyphenylene sulfide (PPS), and polyether ether ketone. (PEEK) and other engineering plastics, fluororubber, silicone rubber and other elastomers, unsaturated polyester and other thermosetting resins, etc. Since the insulating material is an insulating polymer, it becomes easy to install on a conductive stage, and it is easy to replace it even if it is damaged.

The insulating material is preferably bonded by, for example, an adhesive or the like, and/or joined by, for example, processing, on the conductive stage. By adhering and/or joining the insulating material to the mounting table, the sealing performance between the mounting table and the insulating material can be improved, and penetration into the displacement electroless plating bath in the apparatus can be prevented.

The shape of the insulating material can have any shape depending on the shapes of the base material and the third metal. The insulating material is, for example, a flat or curved plate.

When the insulating material is a plate, the average thickness (height) of the insulating material is not limited, but is usually 0.1 mm to 20 mm, preferably 1 mm to 7 mm. The length in the direction in which the material and the third metal are arranged) is not limited, but is usually 1 mm to 5 mm, and the depth (wherein, the depth is the length in the direction perpendicular to the width) is not limited, and is usually longer than the depth of the base material. 0mm～5mm. The insulating material preferably has the same height as the height of the third metal and the base material having the plated film of the second metal when the substrate having the plated film of the second metal is installed in the film forming apparatus of the present invention. Since the insulating material has such a height, the microporous membrane is not only the plated film of the second metal on the substrate, but also the insulating material provided in contact with the substrate and the third metal provided in contact with the insulating material. When the metal is also in contact, the microporous film is in contact with the second metal plating film, the insulating material, and the third metal, which are on the same level by being arranged in contact with each other at the same height. The contact surface between the microporous membrane and these materials no longer has irregularities. If the contact surface of the microporous membrane and these materials has no irregularities, breakage of the microporous membrane can be suppressed. Furthermore, by carrying out the method of the present invention, the site that can be contaminated becomes only the contact surface between the microporous membrane and these materials, so cleaning becomes easy.

The insulating material is provided so as to be in contact with at least a part of the side surface of the base material, for example, when the base material is a pillar and one of the bottom surfaces of the base material has a plated film of the second metal. For example, when the base material is a rectangular parallelepiped and has a plated film of the second metal on one surface of the insulating material, the insulating material is composed of 4 pieces of the surface on which the plated film of the second metal is formed and the opposite surface of the base material. At least one of the surfaces, for example, two surfaces having an opposite surface relationship are provided so as to be in contact with each other. When the insulating material is provided with a base material having a plated film of the second metal, it is preferably provided so as to be in close contact with the surface of the base material on which the plated film of the second metal has not been formed.

The insulating material may be provided so as to sandwich the third metal, that is, to be -insulating material-third metal-insulating material-.

(Microporous membrane)

The microporous film is a porous film for immersion in a substitutional electroless plating bath containing ions of the first metal delivered to the plating film of the second metal on the substrate, and is provided in the opening of the plating bath described below. The microporous membrane can be immersed in the substitution type electroless plating bath containing the ions of the first metal by contacting with the substitution type electroless plating bath containing the ions of the first metal and applying pressure, and in the solid phase substitution type electroless plating method , it is not particularly limited as long as the substitutional electroless plating bath containing the ions of the first metal can pass over the surface of the plated film of the second metal.

The microporous membrane may be a membrane-like microporous membrane like a separator, or may be formed of fibers like a nonwoven fabric. The pore diameter of the microporous membrane is not limited, but is usually 0.01 μm to 100 μm, preferably 0.1 μm to 100 μm.

The microporous membrane may have anionic groups. When the microporous membrane has an anionic group, the anionic group can capture ions of the second metal eluted from the second metal and ions of the third metal eluted from the third metal. Therefore, it is possible to suppress deterioration of the displacement electroless plating bath due to ions of the second metal (eg, nickel ions) derived from the second metal and ions of the third metal (eg, aluminum ions or iron ions) derived from the third metal. In addition, since the microporous membrane having an anionic group has hydrophilicity, the wettability is improved. Therefore, the microporous membrane having an anionic group is easily wetted by the displacement-type electroless plating bath, and the displacement-type electroless plating bath can be uniformly spread on the second metal. As a result, the microporous film having an anionic group also has the effect of being able to form a uniform metal plating film.

The anionic group is not particularly limited, and is, for example, selected from a sulfonic acid group, a thiosulfonic acid group (—S ₂ O ₃ H), a carboxyl group, a phosphoric acid group, a phosphonic acid group, a hydroxyl group, a cyano group, and a thiocyano group of at least 1 species. These anionic groups can capture positively charged metal ions. In addition, these anionic groups can impart hydrophilicity to the microporous membrane. The anionic group is preferably a sulfonic acid group or a carboxyl group. In particular, a sulfonic acid group (sulfo group) is preferable because it can efficiently trap nickel ions.

As a material of the microporous membrane having an anionic group, an anionic polymer can be used. That is, the microporous membrane having an anionic group contains an anionic polymer. The anionic polymer has an anionic group (for example, the above-mentioned sulfonic acid group, thiosulfonic acid group, carboxyl group, phosphoric acid group, phosphonic acid group, hydroxyl group, cyano group, thiocyano group, etc.). An anionic polymer may have 1 type of anionic group independently, and may have a combination of 2 or more types which have anionic group. Preferred anionic groups are sulfonic acid groups.

The anionic polymer is not particularly limited, and may be composed of, for example, a polymer containing a monomer having an anionic group.

Typical anionic polymers include, for example, polymers having carboxyl groups [for example, (meth)acrylic polymers (for example, copolymers of (meth)acrylic acid such as poly(meth)acrylic acid) and other comonomers etc.), or fluorine-based resins with carboxyl groups (perfluorocarboxylic acid resins), etc.], styrene-based resins with sulfonic acid groups [such as polystyrene sulfonic acid, etc.], sulfonated polyaromatic ether-based resins [sulfonated polyaromatic resins] ether ketone resin, sulfonated polyether sulfone resin, etc.] and so on.

The microporous membrane may be a solid electrolyte membrane having ion conductivity. The solid electrolyte membrane has a cluster structure inside, and a displacement electroless plating bath is immersed in the cluster structure. In the case where the solid electrolyte membrane has anionic groups, ions of the first metal such as gold ions in the substitution-type electroless plating bath are coordinated to the anionic groups in the solid electrolyte membrane, so that the first metal ions are allowed to penetrate the solid electrolyte membrane. diffuse effectively. Therefore, by using the solid electrolyte membrane, a uniform metal plating film can be formed.

The solid electrolyte membrane has a porous structure (ie, a cluster structure), and the pores of the porous structure are very small, and the average pore diameter is usually 0.1 μm to 100 μm. By applying pressure, the solid electrolyte membrane can be immersed in a displacement electroless plating bath.

The solid electrolyte membrane may be a fluorine-based resin having a sulfonic acid group. The fluorine-based resin having a sulfonic acid group has a hydrophobic moiety of a fluorinated skeleton and a hydrophilic moiety having a side chain moiety of a sulfonic acid group, and these moieties form an ionic cluster. The ions of the first metal in the substitutional electroless plating bath immersed in the ion clusters coordinate with the sulfonic acid groups of the solid electrolyte membrane and diffuse uniformly in the solid electrolyte membrane. In addition, the solid electrolyte membrane having a sulfonic acid group has high hydrophilicity and excellent wettability, so that the displacement type electroless plating bath is easily wetted, and the displacement type electroless plating bath can be uniformly spread on the second metal. Therefore, by using a fluorine-based resin having a sulfonic acid group, a uniform metal plating film can be formed. In addition, when a fluorine-based resin having a sulfonic acid group is used, the induced polarization generated in the diffusion layer existing between the solid electrolyte membrane and the second metal increases due to the Maxwell-Wagner effect, and as a result, the first metal High-speed transport of ions becomes possible. Such fluorine-based resins are available from DuPont under the trade name "Nafion" series or the like.

The equivalent weight (EW: Equivalent Weight) of the solid electrolyte membrane is usually 850 g/mol to 950 g/mol, preferably 874 g/mol to 909 g/mol. The upper limit value and the lower limit value of these numerical ranges can each be combined arbitrarily to define a preferable range. Here, the equivalent weight is the dry mass of the ion exchange group per equivalent of the solid electrolyte membrane. When the equivalent weight of the solid electrolyte membrane is in this range, the uniformity of the metal plating film can be improved.

The method for adjusting the equivalent weight of the solid electrolyte membrane is not particularly limited. For example, in the case of a perfluorocarbon sulfonic acid polymer, it can be adjusted by changing the polymerization ratio of the fluorinated vinyl ether compound to the fluorinated olefin monomer. Specifically, for example, by increasing the polymerization ratio of the fluorinated vinyl ether compound, the equivalent weight of the obtained solid electrolyte membrane can be reduced. Equivalent weight can be determined by titration.

The film thickness of the microporous membrane is usually 10 μm to 200 μm, preferably 20 μm to 160 μm. The upper limit value and the lower limit value of these numerical ranges can each be combined arbitrarily to define a preferable range. When the film thickness of the microporous film is 10 μm or more, the microporous film is less likely to be broken and excellent in durability. When the film thickness of the microporous film is 200 μm or less, the pressure required for the displacement type electroless plating bath to pass through the microporous film can be reduced.

The water contact angle of the microporous membrane is usually 15° or less, preferably 13° or less, and more preferably 10° or less. When the water contact angle of the microporous membrane is in this range, the wettability of the microporous membrane can be improved.

Examples of microporous membranes (including solid electrolyte membranes) include fluorine-based resins and hydrocarbon-based resins such as POREFLON (registered trademark) WPW-045-80 manufactured by Sumitomo Electric Co., Ltd. and Nafion (registered trademark) manufactured by DuPont Corporation. , polyamic acid resin, Selemion (CMV, CMD, CMF series) made by Asahi Glass Co., Ltd., etc. have an ion exchange function, but it is not limited to these.

The microporous membrane only needs to have a size that can cover the plating film of the second metal on the base material, and may have an insulating material that can cover the insulating material provided in contact with the base material and a second metal film provided in contact with the insulating material. Size on three metals.

(Plating bath)

The plating bath is a vessel for containing a displacement electroless plating bath containing ions of the first metal. The plating bath is formed of a metal material, a resin material, or the like, and includes an opening for bringing the displacement-type electroless plating bath into contact with the microporous membrane. Therefore, a microporous membrane is provided in the opening of the plating bath. Furthermore, since the displacement-type electroless plating bath is accommodated in the space constituted by the plating bath and the microporous film, oxidation of the displacement-type electroless plating bath can be suppressed. Therefore, an oxidation inhibitor may not be added to the displacement electroless plating bath. In addition, by sealing the displacement electroless plating bath with the plating bath and the microporous film, hydrogen can be easily eutectoid in the plating film, and as a result, the solder wettability can be improved.

(extrusion means)

The extrusion means is a means for extruding the plating bath and the base material after the microporous film is brought into contact with the plating film of the second metal on the base material, and is used for extruding the microporous film containing the first metal. The ion-substitution type electroless plating bath is immersed, and the means for delivering the immersed substitution type electroless plating bath containing the ions of the first metal to the plating film of the second metal. The pressing means is not limited as long as it is a means of applying pressure from a displacement electroless plating bath to the microporous membrane and the plated film of the second metal on the substrate, and examples thereof include pressing means using hydraulic pressure.

The pressure that can be applied by pressing means is not limited as long as the microporous film is immersed in the displacement electroless plating bath and can deliver the displacement electroless plating bath to the plating film of the second metal on the substrate. Usually, the pressure is not limited. It is 0.1 MPa to 3 MPa, preferably 0.2 MPa to 1 MPa.

By operating the pressing means, the displacement electroless plating bath containing the ions of the first metal contained in the plating bath is immersed in the inside of the microporous membrane, the ions of the first metal pass through the microporous membrane, and the ions of the first metal pass through the microporous membrane. The film is in contact with the surface of the plated film of the second metal on the base material, and the plated film of the first metal is formed by a solid phase displacement electroless plating method.

Next, a method of forming the first metal on the second metal plated film of the substrate having the second metal plated film by the solid phase displacement electroless plating method using the film forming apparatus of the present invention will be described.

First, in the film forming apparatus of the present invention, a base material having a plated film of the second metal is set so that on the conductive stage, the surface of the base material on which the plated film of the second metal has not been formed and the conductive stage The insulating materials are in contact with each other, and when the microporous film is further provided, the microporous film and the plated film of the second metal are in contact with each other.

Wherein, the base material has a coating film of the second metal on the surface. The base material is an object to be plated, and is preferably a copper base material. The copper substrate is a substrate composed of copper or an alloy containing copper. The substrate can have any shape. The shape of the base material includes, for example, a plate shape (a rectangular parallelepiped shape) or a curved plate shape, a rod-shaped object, a spherical object, and the like. In addition, the base material may be a base material subjected to fine processing such as grooves and holes, and may be, for example, wirings of electronic industrial components such as printed wiring boards, ITO boards, and ceramic IC package boards. The substrate may be a plated film formed on a resin product, a glass product, or a ceramic part. The base material is preferably a copper substrate made of copper.

When the base material is a plate, the average thickness of the base material is generally 0.1 mm to 20 mm, preferably 1 mm to 7 mm, when the thickness of the plating film of the second metal is taken together. For the width (wherein, The width is the length in the direction in which the substrate, insulating material and the third metal are arranged) is not limited, but is usually 2 mm to 20 mm, and the depth (wherein, the depth is the length in the direction perpendicular to the width) is not limited, but is usually 2 mm ~20mm. When the base material is installed in the film forming apparatus of the present invention, it is preferable that the base material has the same height as that of the third metal and the insulating material. Since the base material has such a height, the microporous membrane is not only the plated film of the second metal on the base material, but also the insulating material provided in contact with the base material and the third metal provided in contact with the insulating material. Also in contact, the microporous membrane is in contact with the second metal plated film, the insulating material, and the third metal, which are on the same horizontal plane by being arranged in contact with each other at the same height. The contact surface between the porous membrane and these materials no longer has irregularities. If the contact surface of the microporous membrane and these materials has no irregularities, breakage of the microporous membrane can be suppressed. Furthermore, by carrying out the method of the present invention, the site that can be contaminated becomes only the contact surface between the microporous membrane and these materials, so cleaning becomes easy.

The second metal has a larger ionization tendency than the first metal, and has a smaller ionization tendency than the third metal.

The standard electrode potential (Y) [V with respect to NHE] of the second metal is generally -0.277V≦Y<0.337V, preferably -0.257V≦Y<0.337V.

As a 2nd metal, lead, tin, nickel, etc. are mentioned, for example. As the second metal, nickel is preferable from the viewpoint of the base plating layer in electronic components, in other words, the barrier layer.

In the present invention, the method of depositing the second metal on the surface of the substrate, for example, a copper substrate, to form a plating film of the second metal is not limited, and known in the technical field such as electroplating and electroless plating can be used. technology. The method of depositing the second metal on the surface of the base material to form a plating film of the second metal is preferably a solid-phase method, particularly, a solid-phase electrolytic deposition method and a solid-phase electroless plating method are more preferable. Solid Electrodeposition (SED) is a method in which a microporous membrane such as a solid electrolyte membrane is arranged between the anode and the substrate to be the cathode, and the microporous membrane is brought into contact with the substrate while the anode and the substrate are in contact with each other. A method of forming a metal plated film made of metal on the surface of a substrate by applying a voltage between the two to precipitate metal from the metal ions contained in the microporous film on the surface of the substrate. By employing a solid-phase method, particularly a solid-phase electrolysis method, and a solid-phase electroless plating method such as a solid-phase reduction type electroless plating method, a thick metal plating film can be formed at a high speed.

The average film thickness of the second metal plated on the base material is usually 2 μm to 50 μm, preferably 5 μm to 30 μm. In addition, the average film thickness is the value which averaged the film thickness of 10 places measured using a microscope image etc., for example.

Next, a plating bath for accommodating a substitutional electroless plating bath containing ions of the first metal with the microporous film provided in the opening was installed so that the plating film of the second metal on the substrate was in contact with the microporous film.

In addition, the microporous film only needs to cover the plating film of the second metal on the base material, and can cover the insulating material provided in contact with the base material and the third metal provided in contact with the insulating material. .

A displacement electroless plating bath containing ions of the first metal is accommodated in the plating bath. In addition, the displacement type electroless plating bath can be accommodated at any time as long as it is before the implementation of the solid phase displacement type electroless plating method.

Among them, the first metal has a smaller ionization tendency than the second metal and the third metal.

The standard electrode potential (X) [V relative to NHE] of the first metal is generally 0.337V<X≦1.830V.

As a 1st metal, gold, palladium, rhodium, silver, etc. are mentioned, for example. As the first metal, gold is preferable because it has no surface oxide film, which is a basic condition for bonding, is flexible, and is easily deformed, and is easy to eliminate interfacial voids.

The displacement-type electroless plating bath is a plating solution used in the displacement-type electroless plating method. The displacement-type electroless plating bath contains, for example, a metal compound containing an ion of the first metal and a complexing agent, and may contain additives if necessary. As an additive, a pH buffer, a stabilizer, etc. are mentioned, for example. A commercially available product can be used for the displacement type electroless plating bath.

The displacement electroless plating bath is, for example, a displacement electroless gold plating bath in which the first metal is gold. The displacement type electroless gold plating bath will be described in detail below.

The displacement-type electroless gold plating bath contains at least a gold compound and a complexing agent, and may contain additives if necessary. In addition, since the displacement type electroless gold plating bath does not contain a reducing agent, the management and operation of the bath are relatively simple.

The gold compound is not particularly limited, and examples thereof include cyanogen-based gold salts, non-cyanogen-based gold salts, and the like. Examples of the cyanogen-based gold salt include gold cyanide, potassium gold cyanide, sodium gold cyanide, or ammonium gold cyanide. Examples of the non-cyanide-based gold salt include gold sulfite, gold thiosulfate, gold chloroaurate, gold thiomalate, and the like. The gold salt may be used alone or in combination of two or more. As the gold salt, from the viewpoints of handling, environment and toxicity, non-cyanide-based gold salts are preferably used, and among non-cyanide-based gold salts, sulfite gold salts are preferably used. Examples of the gold sulfite include gold ammonium sulfite, gold potassium sulfite, gold sodium sulfite, and the like, or gold methanesulfonate, and the like.

The content of the gold compound in the displacement-type electroless gold plating bath is usually 0.5 g/L to 2.5 g/L, preferably 1.0 g/L to 2.0 g/L, in terms of gold. The upper limit value and the lower limit value of these numerical ranges can each be combined arbitrarily to define a preferable range. When the content of gold is 0.5 g/L or more, the precipitation reaction of gold can be improved. In addition, when the content of gold is 2.5 g/L or less, the stability of the displacement electroless gold plating bath can be improved.

The complexing agent stably complexes gold ions (Au ⁺ ), reduces the occurrence of Au ⁺ disproportionation reaction (3Au ⁺ →Au ³⁺ +2Au), and as a result has the effect of improving the stability of the substitutional electroless gold plating bath . A complexing agent may be used individually by 1 type, and may be used in combination of 2 or more types.

As a complexing agent, a cyanogen-type complexing agent or a non-cyanogen-type complexing agent is mentioned, for example. As a cyanogen complexing agent, sodium cyanide, potassium cyanide, etc. are mentioned, for example. Examples of non-cyanide complexing agents include sulfites, thiosulfates, thiomalates, thiocyanates, mercaptosuccinic acid, mercaptoacetic acid, 2-mercaptopropionic acid, and 2-aminoethyl sulfide Alcohol, 2-mercaptoethanol, glucocysteine, 1-thioglycerol, sodium mercaptopropanesulfonate, N-acetylmethionine, thiosalicylic acid, ethylenediaminetetraacetic acid (EDTA), pyrophosphate Wait. As the complexing agent, from the viewpoints of handling, environment, and toxicity, it is preferable to use a non-cyanide-based complexing agent, and among the non-cyanide-based complexing agents, a sulfite is preferably used.

The content of the complexing agent in the displacement-type electroless gold plating bath is usually 1 g/L to 200 g/L, preferably 20 g/L to 50 g/L. The upper limit value and the lower limit value of these numerical ranges can each be combined arbitrarily to define a preferable range. When the content of the complexing agent is 1 g/L or more, the gold complexing power is improved, and the stability of the displacement-type electroless gold plating bath can be improved. When the content of the complexing agent is 200 g/L or less, the generation of recrystallization in the substitutional electroless gold plating bath can be suppressed.

The displacement-type electroless gold plating bath may contain additives as needed. As an additive, a pH buffer, a stabilizer, etc. are mentioned, for example.

The pH buffer can adjust the precipitation rate to a desired value, and can keep the pH of the displacement-type electroless gold plating bath constant. A pH buffer may be used individually by 1 type, and may be used in combination of 2 or more types. As a pH buffer, phosphate, acetate, carbonate, borate, citrate, or sulfate etc. are mentioned, for example.

The pH of the displacement-type electroless gold plating bath is usually 5.0 to 8.0, preferably 6.0 to 7.8, and more preferably 6.8 to 7.5. The upper limit value and the lower limit value of these numerical ranges can each be combined arbitrarily to define a preferable range. When the pH is 5.0 or more, the stability of the displacement-type electroless gold plating bath tends to increase. When pH is 8.0 or less, corrosion of the metal base material which is a base metal can be suppressed. pH can be adjusted by adding potassium hydroxide, sodium hydroxide, ammonium hydroxide, etc., for example.

Stabilizers can improve the stability of displacement electroless gold plating baths. As a stabilizer, a thiazole compound, a bipyridine compound, or a phenanthroline compound etc. are mentioned, for example.

As the displacement-type electroless gold plating bath, a commercially available product can be used. As a commercial item, エピタスTDS-25, TDS-20 (made by Uemura Kogyo Co., Ltd.), フラッシュゴールド (made by Okuno Pharmaceutical Co., Ltd.), etc. are mentioned, for example.

In the film forming apparatus of the present invention, after the base material having the coating film of the second metal and the displacement type electroless plating bath are set, the plating bath containing the displacement type electroless plating bath is pressed against the base material by pressing means, Started the solid phase displacement electroless plating method.

By pressing the plating bath and the substrate against each other, the displacement electroless plating bath containing the ions of the first metal contained in the plating bath is immersed in the microporous membrane, and the ions of the first metal pass through the microporous membrane, In contact with the plated film of the second metal on the base material of the microporous membrane, the formation of the plated film of the first metal by the solid phase displacement electroless plating method occurs.

In addition, in the solid phase displacement type electroless plating method of the present invention, the reaction temperature (temperature of the plating bath) is usually 20°C to 95°C, preferably 70°C to 90°C, and the reaction time (plating time) is usually 30 seconds ~1 hour, preferably 1 minute to 30 minutes, the pressure applied between the plating bath containing the substitutional electroless plating bath containing the ions of the first metal and the substrate or insulating material is usually 0.1 MPa to 3 MPa, preferably 0.1 MPa to 3 MPa 0.2MPa～1MPa. By making the reaction conditions into the above-mentioned range, a film can be formed at an appropriate precipitation rate, and the decomposition of the components in the plating bath can be suppressed.

Therefore, the present invention also relates to a method for forming a first metal on a coating film of a second metal by solid phase displacement electroless plating, comprising: (i) disposing a second metal on a conductive loading stage The process of the metal-coated base material, wherein the base material is set so that the surface opposite to the surface of the base material on which the second metal coating film is formed is in contact with a conductive stage; (ii) set on the conductive stage The third metal has a larger ionization tendency than the first metal and the second metal; (iii) the insulating material is placed on the conductive stage, wherein the insulating material is placed between the substrate and the third metal so as to be in contact with the respective materials; (iv) the process of disposing the microporous membrane, wherein the microporous membrane is disposed so as to be in contact with the coating of the second metal on the substrate; (v) disposing The process of the displacement electroless plating bath containing the ions of the first metal, wherein the displacement electroless plating bath containing the ions of the first metal is arranged so as to be in contact with the microporous membrane; and (vi) the ions containing the first metal are to be accommodated The process of extruding the plating bath and the substrate relative to the displacement type electroless plating bath.

It should be noted that in terms of the process order of (i) to (v), as long as a conductive stage, a substrate having a plated film of the second metal, a third metal, an insulating material, a microporous film, and a substrate containing the first metal The relative positional relationship of the substitutional electroless plating bath for metal ions is not limited as described in the above-mentioned film-forming apparatus and film-forming method of the present invention.

In the present invention, it is presumed that the reaction described below occurs, and as a result, the effects of the present invention can be obtained. In addition, this invention is not limited by the following estimation.

By bringing the microporous film of the first displacement electroless plating bath containing ions of the first metal into contact with the plated film of the second metal having a greater ionization tendency than the first metal, the plated film of the second metal becomes ions, and in the displacement type Dissolved in the electroless plating bath, on the other hand, the ions of the first metal from the displacement type electroless plating bath are reduced and deposited on the surface of the plating film of the second metal, and in the reaction for forming the plating film of the first metal, the The surface of the base material coated with the second metal on which the coating film of the second metal has not been formed is brought into contact with a conductive loading stage, the loading stage is brought into contact with the third metal, and the base material and the third metal are separated by an insulating material, As a result, a local battery via the conductive stage is formed between the second metal and the third metal. As a result, the local anode reaction of the third metal proceeds, and electrons generated by this reaction are induced to pass through the conductive stage to induce the second metal. The local cathodic reaction of the first metal on the metal promotes the displacement reaction of the first metal and the second metal, that is, the film formation of the first metal on the plated film of the second metal, and forms a uniform film with a thick film thickness. coating of the first metal.

FIG. 1 is a cross-sectional view schematically showing a state in which a solid-phase displacement electroless plating method is performed using an example of the film forming apparatus of the present invention. In addition, FIG. 2 is an enlarged view of the part shown by the broken line in FIG. 1. FIG.

In the film forming apparatus shown in FIG. 1 , a rectangular parallelepiped substrate 1 having a plated film of the second metal, and a substitutional electroless plating bath 2 containing ions of the first metal are provided. The film forming apparatus of FIG. 1 includes: a conductive stage 3 ; a base material 1 having a plated film of the second metal provided on the conductive stage 3 with the plated film of the second metal on top; Two rectangular parallelepiped insulating materials 4 provided in close contact with two sides; two rectangular parallelepiped third metals 6 provided in close contact with the two insulating materials 4 on the convex portion 5 of the conductive loading table 3; Two further insulating materials 7 of a rectangular parallelepiped provided on the outside of the two third metals 6 in close contact with the two third metals 6; with the plating film of the second metal on the base material 1, the two insulating materials 4. A microporous membrane 8 arranged in a manner that two third metals 6 and two further insulating materials 7 are in contact; a fixing tool 9 for fixing the microporous membrane 8; Displacement type electroless plating bath 2 arranged in such a way; plating bath 10 for accommodating displacement type electroless plating bath 2 ; pressing means (not shown) for pressing plating bath 10 and substrate 1 against each other. In the film-forming apparatus shown in FIG. 1, by operating the extrusion means, the pressure 11 is applied to the microporous film 8 from the displacement-type electroless plating bath 2 to the substrate 1, and the displacement-type electroless plating bath 2 is delivered to the substrate The plating film of the second metal on the material 1 is started, and the film forming method of the present invention is started.

For example, for the substitution type electroless plating bath 2 using gold as the first metal, nickel as the second metal, copper substrate 1' as the substrate 1, and substitution type electroless gold plating bath 2' as the substitution type electroless plating bath 2 containing ions of the first metal 2. In the case of using a titanium loading stage 3' as the conductive loading stage 3, using PEEK 4' as the insulating material 4, and using an aluminum plate 6' as the third metal 6, the portion shown by the dotted line in Fig. 2 is further enlarged. FIG. 3 of FIG. 3 illustrates the movement of electrons in the solid-phase displacement electroless plating method of the present invention.

By bringing the microporous film 8 including the substitution type electroless gold plating bath 2' into contact with the nickel plating film 12 having a higher ionization tendency than gold, the nickel plating film 12 becomes ions and dissolves in the substitution type electroless gold plating bath 2', On the other hand, the gold ions from the substitutional electroless gold plating bath 2' are reduced to precipitate on the surface of the nickel plating film 12, and in the reaction for forming the gold plating film 13, the copper substrate 1 on which the nickel plating film 12 is formed The surface on which the nickel plating film 12 is not formed of ' is brought into contact with the titanium mount 3', the mount 3' (the convex portion 5' of the titanium mount 3') is brought into contact with the aluminum plate 6', and the copper substrate 1 is placed in contact with the aluminum plate 6'. ' is separated from the aluminum plate 6' by PEEK 4', thereby forming a partial battery between nickel and aluminum via the titanium loading table 3', in which a partial anodic reaction of the aluminum plate 6' occurs, and by using this reaction The electrons flow from the aluminum plate 6' to the nickel plating film 12 via the titanium stage 3' and the copper substrate 1', so that the ratio of electrons supplied to the nickel plating film 12 is increased, and as a result, a local cathodic reaction of gold on nickel is induced. Accordingly, the substitution reaction of gold and nickel, that is, the formation of the gold plated film 13 on the nickel plated film 12 is accelerated, and the gold plated film 13 having a thick film thickness can be uniformly formed.

[replacement reaction]

Au ⁺ +e ^- →Au (+1.830V)

Ni→Ni ²⁺ +2e ^- (-0.257V)

[local cathodic reaction]

Au ⁺ +e ^- →Au (+1.830V)

[local anodic reaction]

Al→Al ³⁺ +3e ^- (-1.680V)

Furthermore, in a local battery, due to the difference in ionization tendency of the two metals, the part with high potential (small ionization tendency) becomes the cathode, and the part with low potential (large ionization tendency) becomes the anode, and current flows. However, not only the size of the mutual ionization tendency of the metals, but also the size of the strain, the difference in the size of the metal crystal particles, the difference in the direction of the crystal, and the weight ratio also cause the local battery. The local battery is in a short-circuited state due to the metal phase, so that a local current flows.

The average film thickness of the first metal plated on the second metal is usually 0.01 μm to 25 μm, preferably 0.2 μm to 2.5 μm. In addition, the average film thickness is the value which averaged the film thickness of 10 places measured using a microscope image, an SEM image, etc., for example.

When the first metal is deposited on the surface of the second metal plated on the base material by the solid phase displacement electroless plating method to form a plated film of the first metal, by using the film forming apparatus of the present invention, a small amount of the plating bath can be obtained. The use of it can form the effect of metal coating. That is, in the conventional electroless plating method, a plating film is generally formed on the object to be plated by dipping the object to be plated in a plating bath. In order to immerse the object to be plated in the plating bath, a relatively large amount of plating bath must be used. On the other hand, since the amount of the plating bath used in the film forming apparatus of the present invention is basically only the amount for dipping the microporous film, it is smaller than the amount used for dipping the object to be plated in the related art. Therefore, the method according to the present invention can form a metal plating film by using a small amount of the plating bath.

Furthermore, in the film forming apparatus of the present invention, the third metal that can be consumed by implementing the solid-phase replacement type electroless plating method is not the surface of the substrate on which the plating film of the second metal has not been formed, but is separated by an insulating material. It is installed in parallel with the base material on the same loading stage as that on which the conductivity of the base material is installed. By providing the third metal in this way, even if the third metal is consumed by the solid-phase replacement type electroless plating method, the third metal can be easily replaced, and even if the third metal is ionized and eluted, microscopic The porous membrane is removed for easy cleaning.

The plated laminate produced by the present invention, which includes a base material, a second metal formed on the base material, and a first metal formed on the second metal, can be used, for example, for power element upper electrodes and the like.

Example

Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples, but the technical scope of the present invention is not limited by these.

Example 1

Using the following conditions and the film forming apparatus shown in FIGS. 1 to 3 , a gold plating film was formed by depositing gold as the first metal on the surface of nickel as the second metal by a solid phase displacement electroless plating method.

<Film-forming conditions of solid-phase displacement electroless plating method using gold>

Substitution-type electroless gold plating bath: TDS-25 (manufactured by Uemura Industry Co., Ltd.)

Microporous membrane: POREFLON WPW-045-80 (manufactured by Sumitomo Electric Industries, Ltd.)

Substrate: Nickel plating/Copper substrate

Third metal: aluminum plate

Insulating material: PEEK

Temperature: 70℃

Film forming time: 6 minutes

Pressurization method: hydraulic pressurization

Pressure: about 0.2MPa

A photograph of the gold coating obtained in FIG. 4 is shown. As shown in FIG. 4 , by using the film formation apparatus and film formation method of the present invention, a gold plating film can be normally formed on a nickel plating film on a copper substrate.

Claims (9)

1. A film forming apparatus for forming a first metal on a plating film of a second metal by solid-phase displacement electroless plating, comprising:

a conductive loading platform for setting the base material with the second metal coating film,

A third metal provided on the conductive loading platform,

An insulating material provided on the conductive loading platform,

A microporous membrane for impregnating a displacement type electroless plating bath containing ions of a first metal for delivery to a plating film of a second metal on a substrate,

A bath chamber having a microporous membrane at the opening and containing a replacement type electroless plating bath containing ions of a first metal,

A pressing means for pressing the plating bath and the substrate relatively after the microporous membrane is brought into contact with the second metal plating film on the substrate,

wherein the third metal has a greater ionization tendency than the first metal and the second metal, and the insulating material is provided between the base material and the third metal so as to be in contact with each material when the base material having the plating film of the second metal is provided.

2. The film forming apparatus according to claim 1, wherein when the substrate having the plating film of the second metal is provided, the substrate having the plating film of the second metal, the third metal, and the insulating material have the same height and are on the same horizontal plane.

3. The film formation apparatus according to claim 1 or 2, wherein the conductive mount has a convex portion having a width equal to a width of the third metal at a portion where the third metal is provided, the width being a length in an arrangement direction of the base material, the insulating material, and the third metal is provided on the convex portion of the conductive mount.

4. The film forming apparatus according to any one of claims 1 to 3, wherein the third metal is aluminum or iron.

5. The film forming apparatus according to any one of claims 1 to 4, wherein the insulating material comprises an insulating polymer.

6. The film formation apparatus according to any one of claims 1 to 5, wherein the substrate is a copper substrate, the first metal is gold, and the second metal is nickel.

7. A method for forming a first metal on a plating film of a second metal by a solid-phase displacement type electroless plating method, comprising:

(i) a step of disposing a base material having a plating film of a second metal on a conductive mount, wherein the base material is disposed so that a surface of the base material opposite to a surface thereof on which the plating film of the second metal is formed is in contact with the conductive mount;

(ii) providing a third metal on the conductive loading platform, wherein the third metal has a larger ionization tendency than the first metal and the second metal;

(iii) a step of providing an insulating material on the conductive loading platform, wherein the insulating material is provided between the base material and the third metal so as to be in contact with each material;

(iv) a step of providing a microporous film, wherein the microporous film is provided so as to be in contact with the plating film of the second metal on the substrate;

(v) a step of providing a displacement type electroless plating bath containing ions of the first metal, wherein the displacement type electroless plating bath containing ions of the first metal is provided so as to be in contact with the microporous membrane; and

(vi) and a step of pressing the substrate against the bath chamber containing the replacement type electroless plating bath containing the ions of the first metal.

8. The method of claim 7, wherein the third metal is aluminum or iron.

9. The method of claim 7 or 8, wherein the substrate is a copper substrate, the first metal is gold, and the second metal is nickel.

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